1) Field of the Invention
The invention herein relates to a dual mode tape rule blade arrestor structure that provides for an effective increase in tape rule rewind buffering to prevent excessive blade retrieval speeds that generate high impact sheering forces; the arrestor button of the present invention is pressed upward to temporarily halt tape rule rewinding, but can at the same time also be pressed downward and locked into the full constraint position; as such, the improved structure of the invention herein enhances both tape rule service life and operating safety.
2) Description of the Prior Art
A conventional tape rule is internally comprised of a tape rule blade reel that consists of a center-wound spiral spring at the interior section and a tape rule blade wound around the exterior section, with a hook riveted to the front end of the tape rule blade and the center section of the said tape rule blade reel spiral spring sleeved over a center shaft of a left case half; the front end of the tape rule blade is inserted through a bumper block which is secured by a fastening tab at the bottom section and front end of the left case half and the other side of the bumper block is secured by a fastening tab at the bottom section and front end of the right case half; screws are respectively inserted into screw holes in the said right case half and then fastened into the center shaft and the mounting posts of the left case half to complete the assembly of the tape rule. The conventional product is utilized by pulling out the tape rule blade of the tape rule to an appropriate length during a measurement operation and then releasing the tape rule hook of the tape rule when measuring is finished; since the spiral spring (similar to the type utilized in many spring-loaded mechanisms) inside the tape rule is capable of automatically rewinding the tape rule blade and, furthermore, the rewinding speed increases in proportion to the length the tape rule blade is extended, if the said ruler blade is constructed of metal, the user is susceptible to cutaneous injuries of the hand, which is an inconvenient shortcoming of the conventional tape rule. Furthermore, the faster the rewinding speed, the greater the impact force of the tape rule hook against the bumper block, and since the cushioning performance of the conventional bumper block structure is not optimal, the tape rule hook often becomes dislodged, a serious drawback that renders the conventional tape rule unusable. However, to innovate a more practical and convenient tape rule, the inventor of the invention herein conducted exhaustive research and development based on many years of professional manufacturing experience and, furthermore, subjected the results to extensive testing and further refinement to achieve an even higher level of practical value, which finally culminated in the dual mode tape rule blade arrestor structure of the invention herein.
The primary objective of the invention herein is to provide a dual mode tape rule blade arrestor structure, wherein the arrestor button is pressed upward to temporarily halt tape rule rewinding and, furthermore, the arrestor button is pressed downward and locked into the full constraint position to increase buffering efficiency and decrease rewinding impact force, the improved structure thereby enhancing tape rule operation safety as well as service life.
To enable the examination committee to further understand the structural characteristics and technological content as well as the advantages and innovative features of the invention herein, the brief description of the drawings below is followed by the detailed description of the invention herein.